Category Archives: Cummins 4BT

The synchro-start solenoid can be checked using a voltohmmeter. Disconnect the wiring harness and check the solenoid resistance.  

Engines using the Bosch P7100 fuel injection pump with the RQVK governor are equipped with the synchro-start fuel shut off solenoid to actuate the shut off lever. Both 12 volt and 24 volt external fuel shut off solenoids are available. NOTE: Refer to Procedure (5-31), Fuel Shut Off Solenoid Adjustment/Replacement – Bosch P7100, for instructions… Read More »

The idle adjustment screw provides a stop for the lever at low speed. The adjustment screw can be used to increase idle speed for accessory loading or, if required, to lower the idle speed. The high speed screw is set at the factory and can only be adjusted at a certified fuel pump shop. A… Read More »

The amount of fuel injected and subsequently the speed and power from the engine is controlled by the fuel control lever. Restricted travel of the lever can cause low power. Always check for full travel of the lever when diagnosing a low power complaint.  

The RQVK governors are equipped with an air fuel control (AFC) device to help control emissions. The AFC regulates the fuel to air mixture by sensing manifold pressure. A malfunction of the AFC can cause low power or exces­sive exhaust smoke under load. Leaks at the fittings or a restriction in the tube from the… Read More »

Balance between the governor flyweights and control le­ver position controls the metering of the amount of fuel to be injected. The pump governor performance and setting can affect engine power. Special equipment and qualified personnel are required to verify governor performance. If the seals are broken on the external adjustment screw, the fuel rate may… Read More »

Beginning in 1991, the B series engine used the Bosch P7100 in-line fuel injection pump on higher horsepower automotive ratings. In 1994 all automotive 6B series en­gines will use the Bosch P-7100 in-line fuel injection pump. The B series engine also uses the Nippondenso EP-9 with RSV governor on 250 and 300 horsepower marine rating.… Read More »

Engines with CPL 1579 do not have a resistor in the harness. Engines with CPL 1351 must be wired with the resistor in the harness. The wiring harness used on the electric solenoid style KSB can be inspected using a volt/ohm meter. NOTE: Pin ‘B’ of the metro-pack connector is blank on the electric solenoid… Read More »

Remove the KSB electrical solenoid from the KSB housing. Apply 12 volts to the electrical terminal and ground the hexagonal portion of the element. The magnetic coil of the solenoid must push the plunger outward. If the plunger does not push outward when voltage is applied, the solenoid is defective and must be replaced. Install… Read More »

Remove the temperature switch from the intake manifold. Caution: The switches are not interchangeable. White smoke will be present if the wrong temperature switch is used. Check the part number to be sure the correct temperature switch is used. NOTE: The electrical solenoid style KSB (used on 91 models and newer) uses a 9 0… Read More »